Shear fracture energy of Westerly granite from post‐failure behavior

We consider in this paper the energetic relationship among four different types of measurements: evaluation of shear fracture energy from seismological data, rock mechanics study of post-failure behavior in triaxial compression, measurement of specific surface energy of minerals in a tensile mode, and scanning electron microscope (SEM) observation of stress-induced microstructures. Shear fracture energy can be estimated from post-failure deformation data following an integration scheme recently suggested by Rice. Values so determined for Westerly granite at pressures up to 250 MPa and temperatures up to 700 /sup 0/C are of the order of 10/sup 4/ J m/sup -2/, which is about 2 orders of magnitude higher than the tensile values. Analysis of our data, together with previous room temperature post-failure data, show that the influence of temperature, pressure, and rock type can change the shear fracture energy by an order of magnitude. Microcracking energy can be estimated by multiplying the stress-induced crack area (obtained by stereological technique) and the single-crystal specific surface energy. Energy for the extension of microcracks resolvable under SEM can account for a major portion of the total energy input for pre-failure deformation. However, for post-failure deformation the estimate of microcracking energy is smaller than the totalmore » by at least an order of magnitude.« less

[1]  W. Brace,et al.  Some direct measurements of the surface energy of quartz and orthoclase , 1962 .

[2]  F. Rummel,et al.  Dilatancy and fracture induced velocity changes in rock and their relation to frictional sliding , 1978 .

[3]  John A. Hudson,et al.  Optimizing the control of rock failure in servo-controlled laboratory tests , 1971 .

[4]  J. Brune.  Tectonic stress and the spectra of seismic shear waves from earthquakes , 1970 .

[5]  W. R. Wawersik,et al.  A study of brittle rock fracture in laboratory compression experiments , 1970 .

[6]  R. Kranz,et al.  The effects of confining pressure and stress difference on static fatigue of granite , 1980 .

[7]  R. Stesky.  Mechanisms of high temperature frictional sliding in Westerly granite , 1978 .

[8]  Yoshiaki Ida,et al.  Cohesive force across the tip of a longitudinal‐shear crack and Griffith's specific surface energy , 1972 .

[9]  K. Aki.  Characterization of barriers on an earthquake fault , 1979 .

[10]  J. Handin,et al.  Fracture-surface energy of rocks , 1972 .

[11]  The Fracture Energy of Earthquakes , 1975 .

[12]  John R. Rice,et al.  The stabilization of spreading shear faults by coupled deformation‐diffusion effects in fluid‐infiltrated porous materials , 1976 .

[13]  N. Cook,et al.  Some observations concerning the microscopic and mechanical behaviour of quartzite specimens in stiff, triaxial compression tests , 1973 .

[14]  J. Rice.  A path-independent integral and the approximate analysis of strain , 1968 .

[15]  W. F. Brace,et al.  Permeability from resistivity and pore shape , 1977 .

[16]  W. R. Wawersik,et al.  Post-failure behavior of a granite and diabase , 1971 .

[17]  Shamita Das.  A numerical study of rupture propagation and earthquake source mechanism. , 1976 .

[18]  L. B. Freund,et al.  The mechanics of dynamic shear crack propagation , 1979 .

[19]  Kate Hadley,et al.  Comparison of calculated and observed crack densities and seismic velocities in westerly granite , 1976 .

[20]  R. Martin,et al.  The effect of dilatancy on velocity anisotropy in Westerly granite , 1978 .

[21]  A. McGarr,et al.  Observations relevant to seismic driving stress, stress drop, and efficiency , 1979 .

[22]  R. Kranz,et al.  CRACK GROWTH AND DEVELOPMENT DURING CREEP OF BARRE GRANITE , 1979 .

[23]  J. Rice,et al.  The growth of slip surfaces in the progressive failure of over-consolidated clay , 1973, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[24]  John W. Rudnicki,et al.  Fracture Mechanics Applied to the Earth's Crust , 1980 .

[25]  Paul Tapponnier,et al.  Development of stress-induced microcracks in Westerly Granite , 1976 .

[26]  G. I. Barenblatt.  THE MATHEMATICAL THEORY OF EQUILIBRIUM CRACKS IN BRITTLE FRACTURE , 1962 .

[27]  James D. Byerlee,et al.  Stick slip, stable sliding, and earthquakes—Effect of rock type, pressure, strain rate, and stiffness , 1968 .

[28]  C. Scholz,et al.  Dilatancy in the fracture of crystalline rocks , 1966 .

[29]  M. Kikuchi,et al.  A DYNAMICAL MODEL OF CRACK PROPAGATION , 1973 .

[30]  Teng-fong Wong,et al.  MICROMECHANICS OF FAULTING IN WESTERLY GRANITE , 1982 .

[31]  Y. Ida.  Analysis of stick-slip and earthquake mechanism , 1975 .

[32]  Richard E. Goodman,et al.  Fault and System Stiffnesses and Stick-Slip Phenomena , 1978 .

[33]  Yoshiaki Ida,et al.  The maximum acceleration of seismic ground motion , 1973 .

[34]  M. Ohnaka.  FRICTIONAL CHARACTBRISTICS OF TYPICAL ROCKS , 1975 .